1. Field of the Invention
Methods and apparatuses consistent with the present invention relate to an image display device and correcting a display characteristic thereof, and more particularly, to an image display device which adjusts a gamma according to a saturation value and correcting a display characteristic thereof.
2. Description of the Related Art
In general, a display device has a lookup table (LUT) to convert an input grayscale level into a desirable output grayscale level. The lookup table provided in the display device is prepared for each of RGB colors.
Among the display devices, a liquid crystal display (LCD) has been widely used in various devices such as a monitor, a laptop, a TV, and a mobile communication terminal. Accordingly, there has been a demand for a high display quality of the LCD.
A setting of gamma is an important factor in improving the display quality of the LCD. The setting of gamma is performed according to a gamma curve which defines a correlation between a display luminance and grayscale data, and in order to maintain the display quality at a stable level, a very accurate setting of gamma is required.
Practically, errors frequently occur in various factors of the LCD, such as a distribution among components, a cell gap of a liquid crystal panel, a variation in the thickness of color filter, and a driving voltage. Although a gamma of a panel accurately reaches a target value by controlling these factors, a tolerance for a target gamma may occur.
Since the LCD does not allow an additive color mixture, the LCD uses a lookup table where a gamma characteristic is adjusted for each single color of RGB to display a white color. In this case, the gamma characteristic deviates from an original gamma characteristic in the white color, and due to the deviation of the gamma characteristic in the white color, a grayscale is not accurately expressed in a black-and-white image.
Korean Patent Laid-open No. 2006-0022147 discloses an automatic gamma setting system which measures luminance and corrects a white color gamma and a method thereof. It is important to correct a white color gamma in order to reproduce accurate colors in the LCD. However, besides this white color gamma correction, a white color coordinates correction and a RGB primary color gamma correction are also important. The conventional automatic gamma setting system and the method thereof has a problem in that it corrects the white color gamma only.
Also, in the conventional automatic gamma setting system and the method thereof, the accuracy of color reproduction is determined depending on the accuracy of an output color estimation equation which is created using a small number of color measurement values. Therefore, the accuracy is not guaranteed if a predetermined target value is input.